Posted
by
Soulskill
on Thursday March 10, 2011 @11:52AM
from the bring-a-jacket dept.

astroengine writes "The Keck II infrared telescope on Mauna Kea, Hawaii, has spotted what appears to be the coldest brown dwarf ever detected. Astronomers from the University of Hawaii have managed to constrain its temperature to just shy of 100 degrees Celsius. The object is part of a brown dwarf binary system and is estimated to be 6-15 times the mass of Jupiter. This is an exciting object as it could belong to a so-far theoretical 'Y' class of brown dwarf, a classification that makes objects like this cool example more planet-like than star-like."

Depends on what part of Venus. The surface will melt lead, and there's no plate tectonics (lack of water as a lubricant) because all the H2O is locked up in sulfuric acid clouds. One of the consequences of a locked crust is the inability to recycle the plates (and the chemicals like CO2 that they've pulled out of the atmosphere) via subduction.

You can't. Even if you nuked it to the point of turning portions to liquid, it wouldn't work. Liquids would release their CO2 into the atmosphere, and solids just won't subduct, because the rest of the crust is still locked together like interlocking pieces of a jigsaw puzzle.

You could put a big-enough planet-killing asteroid into it, strip off the sulphur-dioxide-laden atmosphere, and start over, but the entire surface would be molten at that point, and since the rest of the planet is already "squeezed bone dry", you'd just end up back where you started when things cooled down enough.

You could put a big-enough planet-killing asteroid into it, strip off the sulphur-dioxide-laden atmosphere, and start over, but the entire surface would be molten at that point, and since the rest of the planet is already "squeezed bone dry", you'd just end up back where you started when things cooled down enough.

Comets, then? Big ol' chunks of ice from space.

There's some interesting speculation about terraforming Venus in the wik: Terraforming of Venus [wikipedia.org].

I'd want those for colonizing the asteroid belt. That's where the real action is going to be if we ever decide to do anything. Don't need much energy to get out of the individual planetoid's gravity well, hollow them out for living space and raw materials, and we could even experiment with small-scale "ring-worlds".

The asteroid belt is the better bet because of the better availability of raw materials, and the much shallower (practically non-existent) gravity well for transfers between locations in the belt.

Find a rock with decent tensile strength, have bots hollow it out, spin it up, and we can live on the inside surface at 1g - that's a lot healthier than 1/6 g on the moon. And the surface area available from all those small chunks greatly exceeds the total land area of bo

Phobos would be an excellent first choice for this kind of project, as it's already largely hollow, and would make a great base for Mars surface missions. Would also give excellent shielding against cosmic radiation (which is one of the biggest technical challenges of a Mars mission).

The surface will melt lead, and there's no plate tectonics (lack of water as a lubricant)

Um...dude. Water is not a major factor in plate tectonics, which involves huge chunks of the cracked planet being pushed around by molten rock in the planet's mantle. In those dynamics, gravel is a lubricant. And by "gravel" I mean any rock smaller than Norway.

Besides, even if you presume, for the sake of argument, a necessity for liquid libricants, there is, after all, the molten lead you mention...

Superheated water is required for plate subduction. It acts as a lubricant. It's one of the reasons why injecting water into wells to recover more oil triggers earthquakes. Even geothermal power generation [treehugger.com] can cause it.

Molten lead won't do it, if only because it won't flash into steam when the pressure is partially released, and blast out new channels, causing even more movement, more sudden pressure drops, and more steam, until the plate slips enough to release the pent-up strain.

Not sure where you're getting that. Subduction isn't the result of steam explosions. If there's water involved at all, it's supercritical, not gaseous, and doesn't explode so much as filter upward, increasing the gradient that causes the upper plate to be lighter and ride up on the other. The enormous mass of circulating semi-solid mantle below the plates, undergoing asymmetric brownian motion, is by far the bigger player in moving the plates around; from there all it takes is an imbalance in density and

The subducting basalt and sediment are normally rich in hydrous minerals and clays. During the transition from basalt to eclogite, these hydrous materials break down, producing copious quantities of water, which at such great pressure and temperature exists as a supercritical fluid. The supercritical water, which is hot and more buoyant than the surrounding rock, rises into the overlying mantle where it lowers the pressure in (and thus the melting temperature of) the mantle rock

I was thinking about this also. Due to the pressure at the surface water would clearly be a liquid, however it would be pulled down toward the core as it would be heavier then the gasses that make up a star. At some point the temperature would increase enough that it would turn it to steam. If the steam rose (which I don't think would happen as steam would still be more dense then hydrogen and helium) to a point where it would condense, it would actually be raining inside the star,

CAPTAIN: Okay. (puts phone down) Rimmer, make this quick.RIMMER: Sir, I wish to place on record that third technician Lister, David--CAPTAIN: , Rimmer.RIMMER: --smuggled aboard the mining vessel Red Dwarf a consignment of a
hallucinogenic fungi "Titan Mushrooms," more popularly known to the
Space Beatnik community as "Freaky Fungus."CAPTAIN: Is this true?LISTER: Erm, sort of.RIMMER: And on the morning of Febuary the 26th, at 0800 hrs, did engage
in co

we look up at the night sky and see only the bight stars, and assume everything else is vacuum. what if there is a relationship on the order of 100 invisible brown dwarf/ orphan jupiter planetary systems for every regular star system? or 1,000/1 or 10,000/1 or 100,000/1 or more?

i bet as we get better at trying to find exoplanets, we also find a lot of dead dark planetary systems out there. gravitationally bound, but completely without light. a jupiter, just sitting there all alone in the void, with its assemblage of moons/ planets, frozen, and without any light... but not rare at all, all over the place in fact and much more numerous than familiar ignited and main sequence star systems

i mean, star creation should assume a gaussian distribution in terms of star size, right? doesn't that just make simple entropic sense? well look at the wide base of that gaussian curve, below the minimum size needed for ignition: its huge! in overall mass and in number. so if the size spread of star systems is truly gaussian, then there should be orders of magnitude more dark systems out there than ignited systems. i bet we find legions of these systems, or, rather infer legions of them, and just never know for sure, because, of course, they are pitch dark and energetically completely dead

occlusion of other star systems would be the only way to see them. and even then, since they are so small and so far away, and occlusion would be once and probably not ever again, they would be much harder to find than exoplanets, unless they were close to our solar system. they would just become noise in the number of photons hitting earth

This question has lingered in the back of my mind for many years. How do we know there aren't 10^(some huge fucking number) planet-sized objects just floating out there in interstellar space? Assuming they're out there, then it would follow maybe there are 10^(some slightly smaller number) objects out there with a temperature/composition/etc. that's conducive to life of some kind.

If the numbers are right, maybe those candidates outnumber the candidates that orbit stars?

This question has lingered in the back of my mind for many years. How do we know there aren't 10^(some huge fucking number) planet-sized objects just floating out there in interstellar space?

Actually something like that very question has been asked...Back when we first started to get a handle on galactic evolution, somebody noticed that the amount of visible (luminous, that is visible to telescopes, radio telescopes, etc..) matter in galaxies was not enough to account to the visible effects of gravi

i am not describing any of those things. i understand the debate about matter and dark matter and other exotic things we can't see in the universe, and a number of exotic possibilities about where "missing" matter might or might not exist

but i am talking about a more mundane, simplistic issue about star formation and the possibility of a huge amount of "failed" star systems out there

i mean, star creation should assume a gaussian distribution in terms of star size, right? doesn't that just make simple entropic sense?

Since you can't have negative mass, an exponential distribution makes more sense (and is the maximum entropy distribution.) AFAIK, and someone please tell me if I'm wrong, the mass distribution of observed, ignited stars is approximately exponential. This would fit your hypothesis since the exponential distribution is "memoryless," i.e. if you chop off the lower portion of the curve you still have the same distribution.

i see where you are coming from with the exponential distribution. that the colossal titanic star systems are few, and then as you go to smaller self-contained gravitational systems, you get more and more objects/ systems, exponentially increasing in number, down to, well, space dust i guess. i was thinking that since we did see some brown dwarfs and dark systems, that we see a "false" gaussian distribution: that the real gaussian distribution is a much larger hump that we are only seeing the leading edge o

Oh, I agree with your overall idea. Just saying I would be very surprised if the distribution were at all Gaussian. It's almost surely some heavily right-skewed distribution: if not exponential, then probably best modeled by one of the generalizations of the exponential distribution like the gamma or Weibull. If you're making the entropic argument, then the exponential makes the most sense -- Gaussian is maximum entropy on the real number line, but exponential is maximum entropy on the half-open interva

i mean, star creation should assume a gaussian distribution in terms of star size, right?

No, we shouldn't assume star creation has a Gaussian distribution - the universe is neither symmetrical nor uniform. Not even at smaller scales - look at the different types/forms of galaxies for example. The gravitational effects and thus the distribution of proto-stellar matter in a spiral galaxy [wikipedia.org] is going to be different than than the effects and distribution in a barred spiral galaxy [wikipedia.org]. (Let alone the multiple other

"If it didn't ignite, it's not a star - then technically it doesn't even belong on the chart of star sizes."

you are just being legalistic, not making a valid statement which counteracts what i am saying. plus you are talking about galaxies... huh? this is phenomena on a vastly different scale than that is star and planetary system formation

the simple truth is, whenever a star/ planetary system forms, you are talking about a certain amount of mass in the region that serves as a starting point. after some tim

that has nothing to do with this concept. its like saying plate tectonics influences boulder size in a creek bed. of course, plate tectonics raised the mountains that made the creek, but the boulders in that creek are dictated by wind, water, erosion, the composition of rocks in the area, etc. all you have is a "far out man, everything is connected" platitude, and nothing at all to say about the mass of planetary systems

take a count of the largest stars. then just the large stars. the medium sized... you ar

I thought it made it quite clear why I keep talking about galaxies - because they effect local conditions. Local conditions effect what kinds of stars are born and when they are born. What kinds of stars are born and when they are born (and thus how and when they die) affect subsequent populations of stars - and thus the planetary systems that form alongside those subsequent stars.

take a count of the largest stars. then just the large stars. the medium sized... you are increasing in number, right?

i'm through with you. for some reason you believe in talking about completely unrelated tangential topics. other people posting here are able to grasp my point rather simply and address it. but you've got some sort of obtuse mental inability to see a simple point before you and focus on that simple point

you have confronted me with facts. i agree with every fact you've told me. that's not the point

Each and every one of my facts bears on your hypothesis as to the distribution of stellar types. Every scientific, pseudo scientific, mathematical, and pseudo mathematical claim you have made has been rebutted with facts.So what then *is* the point?

i am doubting your social ability to stay within the scope of a given topic

Prior to calling you a troll, I have stayed narrowly within the scope of the

but you, you don't have a point. you have another subject matter. it doesn't say anything material about my hypothesis. you don't refute it. you don't support it. you just babble pointlessly about a subject that is not material

The first sentence of the summary says they "spotted" the brown dwarf. This implies that it was out there and they observed it. The second sentence says that they managed to "constrain" its temperature. This implies that they have control over its temperature. I think that if they have found a way to control the temperature of a brown dwarf (or any other star) that is bigger news than that this is the coolest brown dwarf they have found.

Unfortunately, constrain does not mean that. The summary could have said, "have managed to prove that its temperature is constrained to...", that would have been a correct usage of the word "constrain". The link does not actually use the word constrain relative to the temperature of the star. And in actuality the articles link say that they have calculated that the temperature of this object is 97 degrees Celsius give or take 40 degrees. Which means that even by your interpretation the summary is wrong beca

The first sentence of the summary says they "spotted" the brown dwarf. This implies that it was out there and they observed it.

You are mistaken. When they "spotted" the brown dwarf, it means they added decorative spots to it. So not only do they have the power to control its temperature as you correctly pointed out, but now they can even add polka dots. I'm looking forward to plaid stars.

Astronomers from the University of Hawaii have managed to constrain its temperature to just shy of 100 degrees Celsius.

If these guys have the power to constrain the temperature in some distant galaxy, I wish they will use the power constructively to combat global warming here in this planet. Or at least give a few more days of sunshine to the rust belt USA.

So if the Keck telescope is sensitive enough to detect a (star? large planet?) sized object that is radiating at only at 100c, could it pick up Dyson Spheres? Ringworlds? (But perhaps ringworlds would be more easily detected using transit studies! And, yes I know that they are dynamically unstable!)

If the ring is even the slightest bit uncentered, then it will become more and more uncentered over time, moving in a hula-hoop like rotation around the sun until it eventually touches the sun. You need an active repositioning system to prevent this from happening (like Niven introduced in later books).

Trying to balance a ring world around a star is like trying to balance a dinner plate on the tip of a pencil. Only harder because you can't spin it very fast without killing everyone. With enough planning, you can get it balanced, but even very slight external forces would cause it to start wobbling. With the star's gravity acting on the ring, even the slightest wobble will cascade until the ring collides with the star. A quick googling ca

If there is a nearby brown dwarf, I wonder if there is an opportunity for mining. As I understand it, they have been gathering dust for a very long time so there may be interesting stuff on the surface.